Wire-drawing die and method



Feb. 14, 1939. H. BLOUNT 2,146,788

WIRE DRAWING DIE AND METHOD Filed May 20, 1936 FIG! Fl 6. a FIG. 4

T3 3534 25 2a .24 as a a7 \gJ DVI a if INI/ENTOR y H. BLOUNT 51R MM ATTORNEY Patented Feb. 14, 1939 UNITED STATES PATENT OFFICE ern ElectricCompany,

Incorporated, New

York, N. Y., a corporation of New York Application May 20, 1936, SerialNo. 80,706

12 Qlaim s.

This invention relates to a wire drawing die and method and moreparticularly to a method of and die for drawing wire having an oval orflattened cross section.

In the manufacture of metallic strands for various purposes wherespecial irregular cross sections are required having one transversedimension considerably greater than another at right angles thereto, andwhere such strands are made from circularly cylindrical wire, it isfound in some instances to be desirable to convert the circularlycylindrical wire into elliptically or ovally cylindrical wire as apreliminary step before rolling or drawing into the final irregularform. An illustrative example of such procedure may be found in themanufacture of copper wire or tape having a Z-shaped cros section suchas is used in the manufacture of certain types of electricalcoaxialconductor cable.

Objects of the present invention are to provide a method of and a simpleand durable die, by means of which the method may be practiced. fordrawing circularly cylindrical wire into a strand having a flattened,elliptical or oval cross section, such that the members of the diehaving the drawing surfaces thereon may be readily dismounted for repairand easily and accurately reassembled.

In one embodiment, the invention contemplates a structure comprising aholder in which two complementary blocks are held in juxtaposition by asingle locking member, each block hearing at one end against anindividual stop and at the other end against a common selfadjustingstop, the blocks being formed with complementary arcuate drawing faces.By means of this structure the method may be practiced for makingsubstantially oval or non-circular wire or ribbon.

Other objects and features of the invention will appear from thefollowing detailed description of one embodiment thereof taken inconnection with the accompanying drawing in which the same referencenumerals are applied to identical parts in the several figures and inwhich Fig. 1 is a view in end elevation of a die constructed inaccordance with the invention;

Fig. 2 is a view in section on the line 2--2 of Fi 1;

Fig. 3 is an enlarged detached view in end elevation of one of the twocomplementaryblocks;

Fig.4 is a view in section on the line ii-t of Fig. 3;

Fig. 5-is an end view of the self adjusting looking wedge pin; 7

Fig. 6 isa side view thereof, and

Fig. 7 is an enlarged cross sectional diagram to show the relationbetween the stock being drawn and the die.

In the illustrative embodiment of the inven tion herein shown there ispresented a die constructed in accordance with the invention and adaptedto be used in any suitably arranged familiar type of wire drawingmachine. The foundation of the die is a generally circularly cylindricalbody member 20 with plane, parallel transverse ends and having a partlytapered, partly parallel walled aperture 99 longitudinally oriented fromend to end. A rectangularly cross sectional slot 2i extends transverselythrough the body and is here shown as somewhat below the central levelalthough it may be central or above center to correspond to therequirements of whatever machine is to receive it for use therein.

A pair of complementary rectangularly parallelopipedal blocks 22 and 23are housed in the slot 2| and have a snug sliding .fit therein. Eachblock 22 and 23 has an insert, 24 and 25 respectively, set therein ofhard and wear resisting ma-. terial.

A radial, tapped bore 26 extends down from the top of the block to andpartly beyond the top of the slot 2! and houses a complementarilythread- .ed locking screw 21, whose lower end abuts against the topsurface ofthe block 22 to lock the two blocks in place.

At its right end (Fig. 1) each block 22 and 23 abuts against a. planeface formed on an otherwise circularly cylindrical stop pin, 28 and 29re.- spectively, mounted in corresponding bores in the body and parallelto the axis of the body. The left face of each block 22 and 28 abutsagainst a plane face 3| formed on a common locking pin 30. This pin 30is a circular cylinder having a portion cut away by a plane making anacute angle wit the axis of the pin so that the pin tapers. Furthermoreit has a V groove 32 along the center line of the face 3i. The pin 30 ismounted in a corresponding bore 33 passing through the body 20 at anangle to the vertical central plane thereof equal to the angle of taperof the pin 30.

All the parts described except the inserts 24 and are preferably made ofsuitably selected steel, heat treated as may seem desirable. The inserts2E and 25 are preferably made of tungsten carbide or other suitable hardand wear resisting material. I

Over the centralparts of their mated surfaces the blocks 22 and 23 andthe inserts 20 and 25 are formed identically symmetrical drawingsurfaces asbest shown in Figs. 3 and 4, the arcuately concave contoursshown in Fig. 3 being arcs of circles and the convex contour shown inFig. 4

a sequence of four straight line segments. so that The method and meansfor forming and restoring the drawing surfaces of the inserts 24' outfrom back to front (right to left in Fig. 2)

by means of a suitable drift, after the screw 21 has been backed out atrifle to release its pressure on the block 22. The pin 30 having beenremoved, the blocks 22 and 23 may be driven from right to left (Fig. 1)out of the slot 2| for exchange, examination, regrinding or any otherpurpose. I

To assemble thedie, the blocks 22 and 23 are inserted into the slot 21face to face and pushed or driven in until they stop against the pins 28and 29 respectively. The pin 30 is then inserted into its bore anddriven home, wedging the blocks firmly and longitudinally immovably intoplace against the stop pins 28 and 29. Should one of the blocks be atrifle longer than the other, the pin 30 can rotate accordingly in itshousing and the groove 32 will provide clearance for the overhangingblock comer. Finally the screw 21 is tightened down holding the blocksvertically immovably in the body. A characteristic feature of the diethus made is the shape of the drawin aperture between the concavelyarcuate opposed facets of the inserts 24 and 25. Any transverse sectionof this aperture is formed of two circular arcs enclosing between theman area tapering arcuately to two points. Such a figure is known ingeometry and in the architectural arts as a vesica piscis and as used inthis specification and in the appended claims the words vesica andvesicate are intended to mean this figure and having the form of thisfigure.

In operation the die is used in the same. way a any other die block, thewire. or rod to be drawn being pulled through the laterally elongate andvertically compressed aperture of the die from front to back (left toright in Fig. 2). It is ordinarily not possible to use for wire drawinga die whose drawing surface is presented by more than one piece ormember, for under the heavy stresses of the wire drawing operation, thejoints of a non-integral die will yield and the comers of the componentmembers will open at the joint and will cause either scorings or fins orboth to appear on the product. In the present instance however, when acircularly cylindrical wire or rod 39 is drawn through a die having avesicate aperture of suitably chosen dimensions, the drawing stock doesnot fill the corners of the vesica but is formed inthe die to have aflattened cross section with rounded ends as shown in Fig. 7. Hence thestock does not come into contact with the joints of the die and so isneither scored nor finned by the joints.

When such a vesicate die in two parts-is too worn for further use, itmay be recut without enlargement oi the aperture for renewed use on thesame size of stock (an impossibility with a one piece die) as disclosedin the companion application mentioned above.

The embodiment of the invention herein disclosed is,illustrative onlyand may be modified and departed from in many ways without departingfrom the spirit and scope of the invention as pointed out in and limitedonly by the appended claims.

What is claimed is:

1. A die for drawing wire to substantially elliptically cylindricalform, comprising complementary die members having opposed concavelyarcuate drawing facets forming together a vesicate drawing aperture.

ing die having a vesicate drawing aperture, and means to hold the diemembers together in the 4. A die for drawing wire and comprising fixeddie elements presenting a non-circular drawing aperture of greatercross-sectional area-than that of the wire to be produced thereby.

5. A die for drawing wire and comprising fixed die elements presenting anon-circular drawing aperture having a cross section of greater areathan the cross section of the wire to be produced thereby, the crosssection of the aperture being convexly angular in form.

6. A die for drawing wire and comprising means presenting anon-circular. drawing aperture having a cross section of greater areathan the cross section 'of the wire to be produced thereby, the crosssection of the aperture being vesicate in form.

7. A die for drawing wire and comprising complementary fixed die memberspresenting a noncircular drawing aperture of greater cross-sectionalarea than that of the wire to be produced thereby.

8. A die for drawing wire and comprising complementary fixedjiie memberspresenting a noncircular drawing" aperture having a cross section ofgreater area than the cross section of the wire to be produced thereby,the cross section of the aperture being convexly angular inform.

9. A die for drawing wire and comprising complementary means presenting-'a non-circular drawing aperture having a cross section of reater areathan the cross section of the wire to be produced thereby, the crosssection of the aperture being vesicate in form.

10. A method of drawing wire which comprises the step of advancing awire through a drawing die in which the, drawing aperture of the die isnon-circular and of greater cross-sectional area than the wire issuingtherefrom, theaperture being vesicate in cross-sectional form.

11. A method of making a substantially oval wire which comprises drawinga wire of circular a circular wire through fixed die elements to formthe wire into a. shape having an oval cross-section and then rolling thewire of oval cross-section between rolls to form a ribbon.

HARRY Broom.

transverse aperture and matched to form a draw-

